This study will demonstrate that vaporized cannabis can produce antinociceptive effects compared to placebo in human subjects with spinal cord injury (SCI). A within-subject crossover study of the effects of cannabis versus placebo on spontaneous and evoked pain will be performed. A synopsis of antinociception with mood, cognitive impairment, psychomotor performance, and side effects will be obtained to help evaluate the utility of vaporized marijuana in SCI neuropathic pain.